[18.0][ADD] web_widget_autocomplete: Char autocomplete widget

[ivs-cetmix]

Depends on:

• [18.0][FIX] web_widget_pattern: isolate HOOT filter #3670

Odoo 18 has no backend Char widget that typeahead-fills from a consumer-supplied model method. Partner autocomplete is IAP-only, and web_widget_dropdown_dynamic is a closed select, not typeahead.

This addon registers widget="autocomplete" on Char fields, calls a public @api.model method with the typed string, and on select writes the Char plus any extra Char/Integer keys that exist on the model and in the view.

Task 5613

Made with AI assistance - mostly Cursor - checked manually. If someone is going to call this "yet another AI slope" - do it without using your Claude while reviewing this PR 😆

There is also a dedicated module for the functional testing, it's installed automatically on runboat deployments.
Test flow is really simple and also allows you to discover beautiful cities of Umbria:

• Open a contact form and edit City. Type at least three characters
  (try “Per”, “Ass”, or “cit”) to see Umbria cities.
• Selecting a row writes that name into City. You can still type a city that is not in the list.

[Aldeigja]

Functional LGTM

[ivs-cetmix]

Hey @OCA/web-maintainers don't get me wrong - not asking for a fast track here, but would appreciate someone having a look at this. It's already being in use, however I cannot review my code myself 😄

[yostashiro]

Nice feature! Tried it on Runboat, and the value selection didn't always seem to work when I picked a value using the up/down arrow keys + Enter. It worked fine when I clicked on the value.

[hbrunn]

@ivs-cetmix much less pushiness please. I planned to review this on Friday, but will bump it down the list in order not to reward such behavior

[ivs-cetmix]

@yostashiro thank you, will check!
@hbrunn I wasn't aware of your list, noted.

[ivs-cetmix]

@yostashiro this was fixed, could you please check it again?